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A344963
Numbers k such that (2*k+1)*k!+1 is prime.
1
0, 2, 3, 5, 11, 18, 68, 77, 124, 173, 205, 293, 1037, 1530, 1905, 2342, 3401, 4372, 4679, 5385
OFFSET
1,2
COMMENTS
a(21) > 10^4.
MAPLE
select(k -> isprime((2*k+1)*k!+1), [$0 .. 300])[];
MATHEMATICA
Do[If[PrimeQ[(2*k + 1)*Factorial[k] + 1], Print[k]], {k, 0, 3000}]
PROG
(PARI) for(k=0, 3000, if(isprime((2*k+1)*k!+1), print1(k", ")))
(SageMath)
for k in range(3000):
if is_prime((2*k+1)*factorial(k) + 1):
print(k)
CROSSREFS
Sequence in context: A057652 A025067 A024371 * A231479 A084758 A087582
KEYWORD
nonn,hard,more
AUTHOR
Reza K Ghazi, Jun 07 2021
STATUS
approved